Drugs Affecting Blood Coagulation, Platlet Coag And Fibrinolysis

Question 1

Thrombosis is the formation of what ?

Answer 1

A thrombus in a vessel

Question 2

Thrombosis is initiated by what ?

Answer 2

Pooling of the blood in veins due to sluggish flow

Damaged vessels

Question 3

What is a embolus?

Answer 3

Is a fragment of thrombus that detaches and travels through small blood vessels, may cause pulmonary embolism, MI or stroke.

Question 4

Identify the targets for modifying thrombosis ?

Answer 4

Modify coagulation-venous
Modify platelet aggregation- arterials
Modify clot/ thrombus break down

Question 5

Heparin
Used to treat ?
Mechanism ?
Problems ?

Answer 5

Is a anticoagulant which limits the amount of fibrin being produced
It does this by activating antithrombin (AT) which inhibts thrombin and factor Xa
Poorly absorbed if given orally, give IV, risk of haemorrhage- mild bleeding stop drug! Severe bleeding give protamine sulphate which forms a complex with heparin and stops it having an effect

Question 6

Name the two types of thrombus formation ?

Answer 6

Venous thrombosis- coagulation

Arterial thrombosis- platelet aggregation and some coagulation

Question 7

Warfarin
Works by ?
Problems?

Answer 7

Similar structure to Vit k so binds to factors to prevent them activating.
Factors must be used up first so need to give Heparin for 3 days then change to Warfarin.
Absorption of Vit k a factor and risk of haemorrhage and needs monitoring regularly

Question 8

What are the targets for anti platelet drugs?

Answer 8

Reduce synthesise of TxA2 within platelets
Increase levels of cAnp
Reduce glycoproteins

Question 9

Aspirin blocks ____ enzyme so reduces TxA2 synthesis so won’t clump together. Aspirin alters balance between _____ and _____ so have agragation but not too much.

Answer 9

Cox
TxA2
PGI 2

Question 10

Explain the mechanism of dipyridamole?

Answer 10

Inhibited enzyme that breaks done CAnp- therefore decrease platelet aggregation

Question 11

Explain the mechanism of Clopdogrel

Answer 11

Effects glycoproteins receptors which normally make connections between platelets and epithelial. Also inhibits DAP ( which is released from platelets causing them to swell and connection with more platelets ) so less aggregation.

Question 12

Alter issue is an example of fibrinolytic drug why would this be used and what is its mechanism.

Answer 12

Used in an emergency to break done clot
Fast action
Works by combining with plasminogen to convert into plasmine which is what is needed to break down fibrin

Question 13

Tranexamic acid is an example of anti fibrinolytic drug what does this reduce and when would it be used?

Answer 13

Reduces enzyme that activates plasminogen to become plasmin use in situation to reduce bleeding.